Steam generator control



Sept. 19, 1933. A. DOBLE 1,927,205

STEAM GENERATOR CONTROL Filed May 5, 1930 W D (W & Q my J IN V EN TOR.

A TTORNEYS.

Patented Sept. 19, 1933 UNITED STATES 1,927,205 STEAM GENERATOR cdis'rnor.

Abner Doble,

Berkeley, Calif.

Application May 5, 1930. Serial No. 449,789

2 Claims.

This invention relates to the control of a fluid generator such as a boiler employed for generating steam from water. The invention has been successfully employed in connection with a ve- 5 hicle, particularly an automobile, and I shall therefore preferably describe it in this connection.

The invention the generation of steam in the boiler so that under abnormal conditions, such as when steaming up the boiler from cold, an intense fire is available for heating the boiler while under normal conditions, as when the automobile is moving atrelatively low speed on the level, a mild fire is available.

By providing a mild fire for supplying heat under normal conditions, the efliciency of operation is increased while the noise attendant upon the burning of the fire is slight compared'to when the fire is intense.

It is proposed to increase the fire or the quantity of heat supplied to the boiler by auxiliary means which enable the steaming rate of the boiler to be increased considerably. Such means are also provided in the present invention to aug- 5 ment the mild fire when it is desirable, under nor- 'mal conditions to enable the boiler to supply rel-.

atively large quantities of steam having the desired characteristics.

It is an object of the present invention to provide a steam generator control to regulate the quantity of fire supplied to the boiler so that the fire is efiiciently maintained "in accordance with the conditions of operation.

The invention possesses other advantageous features and objects; some of which, with the foregoing, will be set forth at length in the following description where I shall outline in full that form of steam generator control of my invention which I have selected for illustration in the drawing accompanying and forming part of the present specification. In said drawing I have shown one form of steam generator control embodying my invention, but it is to be understood that I do not limit myself to such form since the invention, as set forth in the claims, may be embodied in a plurality of forms.

The drawing is a diagrammatic showing of a steam power plant embodying the generator control of my invention.

In the form of steam power plant which I have shown as embodying the generator control of my invention a flash, series tube, or forced circulation type boiler 6 is provided by a relatively long tube '7 positioned within a casing 8. Heat is supplied to the boiler by injecting an inflammais concerned with the control of ble mixture into firebox 9 of the boiler past a spark plug 11. The inflammable mixture is created by blowing a current of air through a venturi 12 at the throat of which is placed a carburetor Iii-containing a quantity of fuel. The air is furnished by a blower 16 mounted upon a shaft 17 which is also connected to an electric motor 18 and a steam turbine 19.

The operation of the blower to supply fuel to the firebox and the ignition of the fuel by the spark plug 11 are controlled by an electric cir cuit 21. This circuit is traced from a ground connection 22 to a battery 23, and through a hand switch 24 to contacts 26. These contacts are controlled by a pressure element 27 responsive to pressure in discharge pipe 28 of the boiler. The circuit further includes contacts 31 operable in accordance with the temperature of the boiler through a thermostatic element 32 controlling a rocker arm 33. From the contacts 31 the circuit extends to the electric motor 18 where a field winding 34 and an armature 35 are included in the circuit. The circuit also extends to a solenoid valve mechanism 36 which controls the bypassing of exhaust steam from engine 37 about 8 the turbine. A high tension coil 41 and amechanical interrupter 42 are included in the circuit and are connected to the spark plug 11 so that upon rotation of the shaft 1'7, when the circuit is closed, high tension current is furnished 8 the spark plug.

In operation, the hand switch 24 being closed and the boiler being under such conditions of temperature and pressure that the pressure controlled contacts 26 and the temperature controlled contacts 31 are closed, the field 34 and armature 35 of the motor are energized to rotate the blower at a relatively high rate of speed. If throttle valve 46 is open to admit steam to the engine 37, exhaust steam 9 from the engine passes through a conduit 38 to the turbine 19 so that it supplements the blower to increase the rate of fuel supply to the firebox.

When the boiler is under an abnormal condi tion such as being cold, the thermostat 32 places the rocker arm 33 in such a position that the contacts 31 are closed while additional contact? 47 are open to prevent current from energizing an additional field coil 48 in the motor. As the boiler temperature increases, the thermostat 32 acts to close the contacts 47, while the contacts 31 remain closed. This additional fieldcoil which is energized, under normal boiler condi-- tions, augments or strengthens the series field, 110, thereby causing the motor to turn over at a low rate of speed so that under normal conditions the boiler is supplied with a mild fire due to the reduced speed of the blower. This is advantageous since more economical operation is secured when a mild fire is supplied for a considerable period of time instead of a very intense one for a short period. Further, the mild fire is quiet which is a desirable feature in a vehicle.

When the temperature of the boiler falls considerably, the contacts 4'7 are opened and the contacts 31 remain closed so that only the field 34 is energized and the motor speeds up. This only takes place under abnormal conditions as when the boiler is being steamed up from cold or when working under a heavy load or at high speed. Under these conditions, the additional noise of the fire is not objectionable and will be shrouded by others created by operation of the car.

Under abnormal load or speed conditions the motor 13 is operated at a higher rate of speed than under normal conditions. Also, since the solenoid valve mechanisms 36 is included in the circuit with the windings of the motor which secure high speed operation, the turbine 19 supplements the motor to provide a very intense fire in the boiler during the time that contacts 31 are in closed position. Under normal operating conditions the contacts 47 remain closed so that the motor 18 operates at a low speed. These contacts are opened so that the motor runs at a high speed only when the temperature in the boiler is low, while when the boiler temperature is abnormally high, contacts 31 are opened; This stops the operation of the entire blower mechanism, since although contacts 4'1 remain closed only the additional field 48 is energized, which in itself is incapable of producing rotation of the motor 18.

I claim:

1. A steam generator control comprising a boiler; a blower for supplying fuel to said boiler; an electric motor for driving said blower, said motor having a series field coil and an additional field coil; and means subject to flue gas temperature for controlling said motor, said means at a relatively low temperature energizing only said series field coil, at a higher temperature energizing said series field coil and said additional field coil, and at a relatively high temperature energizing only said additional field coil.

2. A steam generator control comprising a boiler casing; means including a blower for burning a combustible mixture in said casing; a boiler tube in said casing and adapted to be heated to produce steam; an electric motor for driving said blower, said motor having a series field coiland an additional field coil; and a thermostat thermally joined to said tube and subject to said mixture for controlling said motor, said thermostat at a relatively low temperature energizing only said series field coil, at a higher temperature energizing said series field coil and said additional field coil, and at a relatively high temperature energizing only said additional field coil.

ABNER DOBLE. 

